The UN Charter not only lays down specific injunctions for international economic and social cooperation, based on respect for the principle of equal rights and self-determination of peoples, but also has established a special organ—the Economic and Social Council—to conduct the organization's activities in this sphere. Throughout its existence, the UN, together with its specialized agencies, has gradually assumed primary responsibility for assisting the economic and social development of nonindustrialized member nations, most of them former colonial territories that joined the world body long after it was founded. The UN's many projects have become the cornerstone of the development policies adopted by almost all these countries. Since the Covenant of the League contained no provisions for a coordinated program of economic and social cooperation, there can be no comparison between the respective achievements of the two organizations in this respect. Nevertheless, the League performed valuable work in several fields: notably, working to eliminate the illegal sale of women and children, the "white slave" trade; providing assistance for refugees; reducing traffic in opium and other dangerous narcotics; and getting nations to lessen trade restrictions.